Shooting suspect James Holmes applied to join a Colorado gun range last month but never became a member because of his behavior and a “bizarre” message on his voice mail greeting, the range’s owner said Sunday.

Police said James Holmes began buying guns at Denver-area stores nearly two months before Friday’s shooting. He also received at least 50 packages in four months at his home and the University of Colorado that authorities are investigating to see whether they contained materials for the potentially deadly booby traps that police found in his apartment.

At the same time, the quiet 24-year-old was in the final weeks of the first year of a rigorous Ph.D. neuroscience program, where he took a three-part final exam required for students to progress in the program and was scheduled to give a presentation on MicroRNA Biomarkers before abruptly leaving in June.

Holmes is being held without bond on suspicion of multiple counts of first-degree murder after a shooting rampage minutes into a premiere of “The Dark Knight Rises” in Aurora early Friday that left 12 people dead and 58 injured.

He is scheduled for an initial hearing Monday and has been assigned a public defender.